In Patent Document 1 (Japanese Patent Application Laid-Open (JP-A) No. H09-030414), when a plate-shaped vertical skeleton member or the like exists at the near side of a spot welded region at which two or more outer plates and a reinforcing plate are joined, through-holes are provided in the plate-shaped vertical skeleton member, and spot welding is carried out by passing an electrode within these through-holes (see FIG. 3).
Further, in Patent Document 2 ((JP-A) No. 2011-162086), when an outer plate and a first reinforcing plate are joined by laser welding, laser light is irradiated from the outer side of a second reinforcing plate that is disposed at the near side of the outer plate and the first reinforcing plate, and the outer plate and the first reinforcing plate that exist at the inner side of the second reinforcing plate, are laser welded. In this laser welding process, in the second reinforcing plate, a key hole is filled up and laser marks are formed.
[Patent Document 1] JP-A No. H09-030414
[Patent Document 2] JP-A No. 2011-162086
[Patent Document 3] JP-A No. 2012-115876
[Patent Document 4] JP-A No. 2009-154194